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The world’s lightest solid finds myriad other applications

The world’s lightest solid finds myriad other applications
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November 29, 2005 When we first wrote about aerogel, we treated it as somewhat of a technological novelty. Aerogel is 99.8% air and 1,000 times less dense than glass yet it can withstand high temperature, delivering 39 times more insulation than the best fibreglass. This exotic substance was invented in the 1930s but has been refined by NASA in recent times for the purpose of catching space-dust. Now it has been recognised that aerogel’s unique properties are in fact very applicable to some of man’s greatest challenges. Its unique nanostructure offers higher electrochemical surface areas, better mass transport, reduced or eliminated ionic contamination and price competitiveness – in short, lower cost and higher performance compared to current membranes on the market, making it ideal as a high performance electro-catalyst for fuel cells, non-electro-catalysts for emissions control, and aerogel materials for energy storage.

The development of all of these important applications has lead to an investment from the influential GreenShift Corporation. GreenShift’s mission is to develop and support companies and technologies that facilitate the efficient use of natural resources and catalyze transformation environmental change. GreenShift announced that it has entered into an agreement to invest US$500,000 in Aerogel Composite, a development stage materials science company with proprietary technologies involving meso-porous carbon aerogel composites.

Under the terms of its agreement with ACI, GreenShift will purchase 25% of ACI's outstanding stock and receive certain commercial rights in return for GreenShift's investment and its provision of strategic business development and other services. Under its agreement, GreenShift additionally has the option to acquire an additional 5% of ACI.

Aerogel Composites

Aerogels are solid-state substances similar to gels but where the liquid phase is replaced with gas. Aerogels have a highly dendritic tree-like structure and rank among the world's lowest density solids. They have a remarkably high surface area and are very porous and light. Their microstructure and physical properties can be manipulated at the nanometer scale by selection of raw material and modification of manufacturing conditions. Aerogel products can be engineered to exhibit desired thermal, acoustic, mechanical and/or chemical properties. Aerogel materials can be produced as monoliths, thin-films, powders, or micro-spheres to respond to given application requirements.

There are three major types of aerogels: inorganic, organic and carbon aerogels. Inorganic aerogels are obtained by supercritical drying of highly cross-linked hydrogels synthesized by polycondensation of metal alkoxides. Silica aerogels are the most well known inorganic aerogels. Organic aerogels are synthesized by supercritical drying of the gels obtained by the sol-gel polycondensation reaction of resorcinol with formaldehyde in aqueous solutions. Carbon aerogels are prepared by pyrolyzing organic aerogels in an inert atmosphere.

Carbon aerogels are electrically conductive and have very high porosity of over 50%, with pore diameters ranging from 2 to 50 nanometers, and extremely high surface areas ranging between 400-1000 square meters per gram.

ACI's Patented and Proprietary Technologies

ACI has patented nanotechnology for the preparation of aerogel composites for a wide variety of applications. Applications of ACI's Hyrogel carbon aerogel supported catalysts are planned to include hydrogen powered stationary and mobile PEM fuel cells, direct methanol fuel cells (DMFC) for portable electronic devices such as laptop computers and cell phones, and other metal oxide aerogel supported catalyst for catalytic converters for gasoline and diesel powered vehicles and other internal combustion engines.

Hiro Hara, president, chief executive officer and founder of ACI, said that: "We have many years of development into our technology and we are very much looking forward to bringing the many applications of our technology to market. We expect that GreenShift's investment will accelerate this process and we are pleased to have their support."

The unique nanostructure of the ACI carbon aerogel offers higher electrochemical surface areas, better mass transport, reduced or eliminated ionic contamination and price competitiveness. This translates into both lower cost and higher performance when applied to current membranes on the market. ACI's initial products are high performance electro-catalysts for fuel cells, non-electro-catalysts for emissions control, and aerogel materials for energy storage.

ACI's electro-catalyst products achieve equivalent catalytic performance at one half to one tenth the precious metal loading commonly achieved by current technology. These catalysts are the primary cost drivers in all of the markets ACI is addressing. ACI's technology directly addresses the cost of fuel cell systems by lowering the platinum cost in the membrane electrode assembly (MEA).

For example, ACI's Hyrogel Carbon Aerogel Supported Platinum Catalyst (CASPC) reduces the platinum requirements of hydrogen powered proton exchange membrane (PEM) fuel cells by over 90% from recently prevailing levels. Based on industry feedback, ACI believes that its electro-catalyst is the most efficient and most economical PEM electro-catalyst available today.

ACI has also produced catalyst coated membrane (CCMs) or three piece membrane electrode assemblies ("MEAs") for PEM fuel cells, incorporating its proprietary Hyrogel electro-catalyst. These CCMs/MEAs have achieved a performance of one watt per square centimeter, requiring less than 0.1 milligram per square centimeter of platinum on the cathode. Based on industry data, ACI believes that this performance is unmatched.

Additionally, in catalytic emissions control systems, ACI's technology reduces precious metal loading and therefore cost. In 2003, the US$4 billion market for emission control catalysts utilized US$3.19 billion of platinum group metals. This market is expected to grow significantly due to increased regulation, stricter enforcement and rising demand for diesel automobiles in Europe and the U.S.

Other potential applications of ACI's platform technology include materials for ultra-capacitor electrodes, hydrogen and energy storage, catalyst for fuel reformers, specific gas sensors, biosensors, and desalination of water.

"We see Mr. Hara's technology as another remarkable example of leveraging an incremental improvement in efficiency into dramatic environmental gains," said Kevin Kreisler, GreenShift's chairman and chief executive officer.

"ACI's technology reduces the need to consume virgin precious and other metals and, consequently, manufacturing costs for environmentally-beneficial products such as fuel cells and emissions controls. We believe that decreased costs for such products will eventually equate to increased production and more environmentally proactive products in the hands of more consumers. Technologies like ACI's have the potential to initiate cascade effects in environmental gain and we intend to support ACI in any way we can. We are very excited to include this important and timely company and their technology in our portfolio."

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Brian Hall
Put huge cubes into orbit to absorb and de-orbit space junk.